It's no secret that some of Valve's greatest hits all used the same engine - the Source engine - and many of the engine's assets merge seamlessly between games. In fact, the first five chapters (and one chapter from Half-Life 2 Episode 1) are playable in the Left 4 Dead 2 setting - though there are some requirements necessary to get them working properly. Some of the most impressive Left 4 Dead 2 campaigns are simply Half-Life 2 maps ported to the zombie FPS. Some maps, though, aren't found on the workshop - especially those that require other games to be installed. With the Steam Workshop available for the game, the modding scene took off, with hundreds (if not thousands) of maps available for players to download with one click. Updated Septemby Erik Petrovich: The modding community behind Left 4 Dead 2 is one of the most prolific and creative communities out there. By playing these custom campaigns, players are able to travel to other areas that have been affected by the Green Flu. New voice lines were recorded, adding to the setting of the campaign. Some of the campaigns are simple, while others require the player to solve puzzles. RELATED: Most Terrifying Monsters in Video Games

Some campaign creators go above and beyond, creating custom skins for the infected and escape vehicles. Despite having fun campaigns and memorable characters, Left 4 Dead 2is also known for the mods and custom campaigns fans have made.

The game features seven different campaigns, including the campaigns from the original Left 4 Dead. Left 4 Dead 2 is a zombie survival game that was developed by Valve.

Best modded zombie maps